Abstract:

The plate count method has been used as a classical method at home and abroad for the aerobic bacterial count in cosmetics, which is simple to operate, but it takes a long time to complete the entire detection process. With the development of microbiological technology, a variety of rapid microbial counting methods based on various principles have been gradually developed. By comparing the advantages and disadvantages of the plate count methods and various rapid microbial counting methods for the aerobic bacterial count in cosmetics, the length of detection time, the accuracy of the aerobic bacterial count, and the feasibility of rapid microbial counting method in the detection of aerobic bacterial count in cosmetics were comprehensively considered. It can be concluded that the fluorescence microscopy counting method and flow cytometry counting method have potential in the detection of aerobic bacterial count in cosmetics. The reasons are as follows, TEMPO^® counting method, molecular biology counting method, ELISA （enzyme-linked immunosorbent assay） counting method, optical biosensors counting method, and mass spectrometry counting method have high specificity for bacteria and are only suitable for quantification of certain microorganisms, while microbial metabolism counting method, microfluidics counting methods, MicroSnap^TM counting method, and Simplate^TM counting method require microbial culture, thus preservatives in cosmetics will affect the accuracy of the total number of microorganisms in the sample. Although the fluorescence intensity counting method is suitable for the aerobic bacterial count in cosmetics, its sensitivity is quite low. The fluorescence microscopy counting method and flow cytometry counting method are suitable for the aerobic bacterial count in cosmetics for two reasons. The first reason is that the fluorescence microscopy counting method and flow cytometry counting method directly count the number of microorganisms in the sample so that the detection time is shorter. The second reason is that there is no need for microbial culture. Therefore, there is no need to consider the inhibitory effect of preservatives in cosmetics on microbial growth, so that the detection accuracy is higher. The introduction of rapid microbial counting methods into the standard system of the aerobic bacterial count in cosmetics, as a supplement to the current standard, is of great significance for aerobic bacterial count in cosmetics.

Key words: cosmetics, aerobic bacterial count, plate count method, rapid microbial counting method